1. Field of the Invention
The invention relates to tools for removing screws. The invention also relates to locksmith's tools and tools for removing one-way screws.
2. Description of the Prior Art
The one-way or nonretractable screw is disclosed in U.S. Pat. No. 131,843 to Brooks, in 1872, and remains in commercial use today. A number of other one-way screws have been patented since the Brooks, but the Brooks screw appears to be the only structure widely used. The one-way screw is used to secure any hardware item that is intended to be nonremovable, for example hinges and latches in public places where a person could have the opportunity to remove the item unobserved. In addition, locksmiths use one-way screws to secure locks and dead bolts, thereby preventing an intruder from removing the lock or dead bolt with an ordinary screw driver.
While the one-way screw successfully resists many removal attempts, at times the screws must be removed in order to replace or service the mounted lock or other hardware piece. In locations where the screw head is at the bottom of a narrow well, drilling may be the only practical method of removal. In more accessible locations, the screw can be slowly removed with a punch. Neither method is satisfactory because of the long time necessary to accomplish the job.
Others seeking to remedy the problem have designed one-way screws having modifications allowing the use of special tools to remove the screw. For example, U.S. Pat. No. 3,673,912 to Herr discloses a Brooks style one-way screw with a special notch along the slot of the screw. The Herr patent then discloses a special screw driver having a notch engaging projection for removing the screw. While the described modification and special tool provide one possible solution to the removal problem, it is of no aid in removing presently installed Brooks style screws.